The current set of cases in SecureTransport's recordTLSVersion() explicitly leaves out kTLSProtocol13 because that enum value isn't defined in older OSX headers.  Unfortunately, this makes compiling with newer OSX headers broken since it's an unhandled enum value.

We should either use a `default:` case to ignore it (it's already being ignored anyway), or find the right #ifdef to determine if the enum is defined and conditionally capture it.